The height of their power was during the time of Utumno, when there were a thousand. Only about 5 or 6 balrogs stopped Ungoliant from killing Melkor. Feanor killed 5 or 6 most likely, maybe less. But they are very unique.
Nanye i ne Anduril i macil Elendilo
Lercuvanten i moli Mordoreo
Turgon aran Gondolin tortha gar a matha, i vegil Glamdring gud dae lo, dam an Glamhoth.
Doubt it. The Silmarillion explicitly says Feanor was the best of the Eldar. Read the direct quote from ares on the previous page. Fingolfin is very very strong and a good warrior, and it would be an epic fight, but Feanor wins more often than not.
Which is interesting, because The Silmarillion also explicitly states that Fingolfin was the strongest, most headstrong, and most valiant of Finwe's children. Feanor by comparison is said to be the most skilled of mind and hand, referring to his gem crafting abilities.
"For Fëanor was made the mightiest in all parts of body and mind: in valour, in endurance, in beauty, in understanding, in skill, in strength and subtlety alike: of all the Children of Ilúvatar, and a bright flame was in him."
― The Silmarillion, Of the Sun and Moon and the Hiding of Valinor
I get that Fingolfin was badass strong, and probably has a wealth more combat experience, so reflecting on that last point, he definitely has that in his favor. However, without any concrete knowledge to go off of, Feanor is implied by the narrator to be the best of the best. Certainly the strongest Eldar in the First Age, save Thingol.
"Feanor was the mightiest in skill of word and of hand, more learned than his brothers; his spirit burned as a flame. Fingolfin was the strongest, the most steadfast, and the most valiant. Finarfin was the fairest, and the most wise of heart; and afterwards he was a friend of the sons of Olwe, lord of the Teleri, and had to wife Earwen, the swan-maiden of Alqualonde, Olwe's daughter."
- The Silmarillion, Of Eldamar and the Princes of the Eldalie
According to this, Feanor was not as strong as Fingolfin, nor as fair as Finarfin.
Except, Feanor has several of these quotes to his name. He has the one Moose posted and he has the one Allankles posted ("mightiest of the Eldar save Feanor only"). But he has more he is mentioned as being "of all the Noldor, then or after, the most subtle in mind and the most skilled in hand” and "the mightiest of the Noldor, of whose deeds came both their greatest renown and their most grevieous woe". (And of course several quotes citing him as the greatest of the Eldar/Noldor.)
All of those I'd say outweigh the one quote about Fingolfin.
The feats are entirely comparable. If anything, holding out against the Balrogs is even more impressive considering they drove back Ungoliant. Something a presumably more powerful version of Morgoth was unable to do.
Is this a competition between what is more combat-relevant: skill (of hand) or strength? Is there any quote that better describes what "skill of hand" means? Because paired as it is with skill of "word" it can easily be interpreted as combative (in sword use) juxtaposition of speech, or it can be interpreted as a skill of art--just as speaking (oration/poetry) is.
F*ckin' authors and their flowery, vague language, man. It's like the "Greatest or most powerful Sith Lord" shit all over again.
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